Useful For

Progesterone, a C21 steroid, is one of the female sex hormones. In conjunction with estrogens, progesterone regulates the female accessory organs during the menstrual cycle. It also functions in preparing the uterus for the implantation of blastocysts and in maintaining pregnancy. Progesterone is produced by the corpus luteum in nonpregnant females, whereas the placenta becomes the primary source during pregnancy. Blood progesterone is often used to ascertain if ovulation did occur in a menstrual cycle. Since progesterone is an obligatory precursor of corticosteroids and androgens, the adrenal glands and testes are minor sources of progesterone in the blood stream. Notes: 1)Elevated progesterone levels may be indicative of adrenal or testicular tumors.